ENT/LIS/GEO 530
The Constitution says…Article 1, Section 2 of the United States
Constitution: “Representatives and direct taxes shall be
apportioned among the several states which may be included within this union, according to their respective numbers ... The actual Enumeration shall be made within three years after the first meeting of the Congress of the United States, and within every subsequent term of ten years, in such manner as they shall by law direct.”
Basics of Census 2000Short Form
Survey of 100% of the population
Questions about the basic demographic characteristics
age, race, number of people in a housing unit
Long FormSample of one in six
housing unitsBasic demographic
questions PLUS questions
about socioeconomic topics education, income,
housing characteristics, employment, and disability status
Basics of Census 2010Short Form
Continue constitutionally mandated short form counting 100% of the population
Long FormReplaced by the
American Community Survey (ACS)
Census count is focused on coverage
American Community Survey is focused on content
Basics of the American Community Survey
A nationwide, continuous monthly surveyAnnual sample size = around 3 million
addressesData products will be released annually
Profiles available every year for communities of 65,000 or more people
Profiles available in 3 to 5 year estimates for communities with fewer than 65,000 people
Benefits of the ACSProvides timely data between the decennial
censusesExamples in past decade when would matter?
Provides ability to monitor trends in local communities between censusesExamples of how useful?
Permanent, professional interviewersWhy matter?
But keep in mind …Estimates
Sample is small and requires aggregation of data over time for smaller locations
Point in time versus period dataCounting on April 1 of census year versus
counting continuously throughout yearMargins of error and confidence
intervalsFigures are an estimate with a confidence
interval of 90%
Availability for particular places
Reidsville, NC has 14,485 (Census 2000)
5-year estimate (2005-2009) available now
Burlington, NC has 49,038 (ACS 2006-2008)
Two 3-year estimates (05-07 & 06-08) and one 5-year estimate.
Greensboro, NC has 242,817 (ACS 2006-2008)
Any 1-year, 3-year, 5-year estimate could be used.
Point in time versus period data
Census American Community Survey
Point in time dataReference point is April 1
Period dataReference period is past
12 months
Differences in QuestionsCensus American Community
Survey31. INCOME IN 1999a. Wages, salary,
commissions, bonuses, or tips from all jobs - Report amount before deductions for taxes, bonds, dues, or other items.O Yes
Annual amount – Dollars $[ ][ ][ ],[ ][ ][ ].00O No
47. INCOME IN THE PAST 12 MONTHS.
a) Wages, salary, commissions, bonuses, or tips from all jobs.
Report amount before deductions for taxes, bonds, dues, or other items Yes -->
$____________________.00 (TOTAL AMOUNT for past 12 MONTHS)
No
Margins of ErrorCensus data has margins of error built in;
ACS data publishes the MoECensus Bureau data has a confidence interval
of 90%How would we interpret this?
Albany County 258, 649 +/-2,191We are 90% confident that the true value is
between 256,458 and 260,840. There is a 10% probability that the estimate would be outside this range.
Putting it into practice
Question Questions to ask
• I’m looking for recent information on number of people by age and race for census tracts in Greensboro, NC.
Time?What is recent? 2000 or
2005-2009 data?Geography?
Census tractsTopic of question?
Age and race of people
American FactFinder (AFF)Contains
American Community SurveyCensus 2010 & 2000 dataEconomic CensusPopulation estimatesAnd more!
http://factfinder2.census.gov/
References Herman, E. (2008). The American Community Survey: An introduction to the
basics. Government Information Quarterly 25, 504-519.
Mather, M., Rivers, K. L., & Jacobsen, L.A. (2005). The American Community Survey. Population Bulletin, 60(3), 3-20.
North Carolina Office of State Budget & Management. (2008). NC SDC 2008 Annual Meeting Materials. Retrieved January 27, 2009 from http://www.osbm.state.nc.us/ncosbm/facts_and_figures/state_data_center/AnnualMeetings/
North Carolina Office of State Budget & Management. (2008). North Carolina is counting on you! Retrieved January 27, 2009 from http://www.osbm.state.nc.us/ncosbm/facts_and_figures/census/nc2010/
Taeuber, C. M. (2006). American Community Survey for Community Planning. Oxford: Trafford Publishing.
U.S. Bureau of the Census. (2008). A compass for understanding and using American Community Survey Data What general data users need to know. Retrieved December 1, 2009 from
http://www.census.gov/acs/www/Downloads/ACSGeneralHandbook.pdf